Which concrete anchors to use for toilet?

Hello Folks,

We have tile over a 2" mud bed in the bathroom. I need to fasten the toilet with 5/16" lag bolts per its instructions. It's a back-discharge (Yorkville) so these screws aren't going to a flange ring but right into the floor.

In Europe I always used big nylon mollies (Fischer) but I can't find those here, at least not this big. Instead, there is a myriad of metal fasteners in the stores.

What do you guys use to bolt a toilet to concrete? Or if you never mounted a back-discharge unit what do you use to secure a flange into a concrete floor?

Of course I could drill through to the plywood but that stuff always seems a bit flimsy to me. Once I did that and managed to tear the wood right out when turning the bolt (and I am not Arnold).

Regards, Joerg.

My personal preference for attaching anything to concrete is lead ferrells. You drill a pilot hole, tap the ferrell in flush, then use sheet metal screw into the ferrell. For a toilet especially, I use stainless steel sheetmetal screws. There are other types if screws and bolts that can be used, Tapcon is one that I have tried, but the ferrells seem to be easier for me. I use a rotary hammer/drill using a SDS bit.

I use plastic anchors with 2" stainless steel screws. I have lead anchors but they are shallow ones. Not for anchoring toilets. If I could find longer lead ones I'd use them for toilet flange mounting to concrete.

Tapcons are sweet but I'm too dumb to use them. I lose the bit or I don't drill the hole properly.

Thanks, guys. I'll try to find plastic anchors then. Haven't seen any good ones but I guess I have to look harder. The Fischer anchors I brought from Europe have dried up by now and became brittle. Plus 10mm OD anchors wouldn't have been big enough for 5/16" screws anyway I guess.

The fun will be the usual, drilling through porcelain tile. Don't ya hate that?

Regards, Joerg.

Where does one get those plastic anchors?

Well, did a pilgrimage to all of them, HD, Lowes, OSH, ACE and smaller ones. Nobdoy carries plastic anchors for 5/16" lag screws. Just itty-bitty ones. Ok, I know they can be bought at any hardware store in Germany but it takes so long to send them from there.

Any ideas where to buy these in the US?

Regards, Joerg.

Why not use the lead ones? In my opinion, they're better than plastic anyway and are available in the size you need.

Hello Gary,

Yes, maybe I'll give lead anchors a shot if I can't find nylon. Meantime I have read elsewhere on the web that if you want good nylon anchors you need to have a friend in Europe send them. Not good news.

One reason why I like heavy duty nylon ones (Fischer etc.) is that they keep the head under tension and you can put them in with the slots in the direction the screw might have to veer a bit. They are quite forgiving. A lead anchor can only take a screw exactly straight. For some reason those holes in the toilets aren't exactly per spec. I have seen them under 5-3/4" on center where the spec says 6", and not much slack in the holes for a 5/16" screw. Somehow that was different in the old days. The worst case is you have the perfect holes and anchors in there and then it won't fit. On back-discharge toilets it seems there is only one try.

Regards, Joerg.

Wait a minute! You aren't trying to bolt the toilet directly to the floor are you? The flange is anchored to the floor with several screws then the toilet is attached to the flange with two tee bolts that fit through a slot in the flange then through the holes in the base of the toilet. I'd set the flange in place, mark the spots for the screws, pull the flange off, and drill the holes. Do it that way and I don't think you can miss having the ferrells straight enough. You do have to orient the flange so that the tee bolts will come up in the proper location.

Hello Gary,

This isn't a normal toilet. It is a Yorkville which has four mounting holes, two in back and two in the bottom. The waste outlet is in back about 4" off the floor level. It is bolted to the back wall against a neoprene gasket. This has to be compressed but not too much so you won't know the exactly hole locations for the other two screws in the bottom until it's tied to the wall. Since the neoprene gasket has to be glued you get one shot at it.

The holes are drilled per spec sheet and checked by roughly placing the toilet without gasket. Also, the surfaces against which the heads of these bottom screws are tugging are sloped. No idea why they did that.

With lag shield anchors the screws will not go in unless the loactions line up very exactly with the holes in the toilet. No big deal with nylon anchors except that it seems I have to have them sent over from Europe. There you can buy some heavy-duty versions in 10mm or 12mm at every hardware store. That's how back-discharge toilets are bolted to the floor over there since nearly all houses have concrete floors.

Regards, Joerg.